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Functional somatic syndrome (FSS) occurs in as many as 30% of patients in general medical practice, but it is infrequently a topic of formal instruction. Many physicians feel uncomfortable with medically unexplained symptoms and are unfamiliar with how to assess or manage them. Traditional medical approaches can be ineffective and can contribute to iatrogenic or adverse physiologic effects in patients. Physicians treating patients with FSS should not only consider standard medical tests, but they should also try to gain a deeper behavioral understanding of the mind-body connections that underlie the presenting symptoms. Osteopathic physicians, with their emphasis on holistic patient care, are in a key position to treat patients with FSS. This review provides a brief recapitulation of the literature and illustrates key factors in the assessment and management of FSS.

Functional somatic syndrome (FSS) has been around for thousands of years.1 Various terminology has been used to describe FSS throughout the years, including hysteria, somatoform disorders, medically unexplained symptoms, and fashionable illnesses.1 Current terminology in the Diagnostic and Statistical Manual of Mental Disorders, fifth edition,2 includes somatic symptom disorder, conversion disorder, and illness anxiety disorder. However, for the purposes of the present review, the term functional somatic syndrome will be used to describe a combination of symptoms that cannot be fully explained by pathologic conditions or diseases and that cause functional impairment or disruption of everyday activities, without evidence of the patient intentionally feigning their symptoms. Functional somatic syndrome is a term that patients find minimally offensive when describing their condition, but it is not suggested as formal diagnostic terminology.2 The aim of this review is to impart a framework for successful assessment and treatment of patients with FSS.

Functional somatic syndrome is commonly encountered in the general and specialty health care settings.3 A review on the prevalence of somatoform disorders and medically unexplained symptoms in primary care found that at least 1 medically unexplained symptom was observed in 40% to 49% of all primary care patients.4 In a neurologic practice, approximately one-third of new patients were found to have symptoms not fully explained by neurologic causes.5 Nevertheless, physicians fail to consider FSS in the differential diagnosis as much as 90% of the time when presented with nonspecific symptoms that are unexplained by medical tests or known diseases.6 Additionally, physicians are more likely to seek to medically explain symptoms regardless of the available evidence.7 In the present article, I review the literature on FSS and describe assessment and management techniques for this condition.

Assessment and Diagnosis

Appropriate diagnosis of FSS is just as important as that of medically explained illnesses, and the rate of misdiagnosis in patients presenting with FSS is only about 4%.8 Failing to consider FSS can result in detrimental outcomes from both the clinical and economic perspective. Patients with FSS present with nonspecific symptoms that typically include myalgia, joint pain, back pain, headache, fatigue, feeling faint or dizzy, chest pain, heart palpitations, trembling, diarrhea and constipation, insomnia, and cognitive issues (eg, lack of attention, loss of memory). These symptoms are often within the realm of normal human experience.9 Clusters of nonspecific symptoms have been labeled as chronic fatigue syndrome, Lyme disease, fibromyalgia, irritable bowel syndrome, and atypical chest pain.10 Henningsen et al11 described nearly 30 different labels for conditions in which patients present with FSS. Nevertheless, several studies have found that symptoms do not cluster into easily defined, distinct syndromes and should not be presumed to be independent.12,13 When symptoms are clustered into groups, managing subsets of those symptoms as unique conditions can lead to misdiagnosis, ineffective treatment, and failure to recognize and manage the underlying cause of the individual symptoms.

Patients with FSS have been shown to have more than twice the use and costs of health care services than a patient with a medically-confirmed illnesses.14,15 For example, Sicras-Mainar et al16 found that compared with a reference population, patients with fibromyalgia had €5010 more in health care costs, had more comorbidities, had an average of 6 more outpatient visits annually, missed more days of work, and used more pain-relieving medication. Also, patients with fibromyalgia were more likely to undergo surgical procedures compared with patients with a rheumatic disorder.16 From a clinical perspective, as many as 55% of patients with FSS whose symptoms are managed with standard medical approaches will experience adverse effects because the underlying cause of the symptoms is not addressed.17

Functional somatic syndrome has a strong correlation to psychological conditions, such as depression and anxiety, as well as a history of trauma or abuse. Depressive episodes, negative life events, the number of medically unexplained symptoms at baseline, attributional style, autonomic sensations, and catastrophic cognitions should be considered when a patient presents with FSS.18 Studies found that 80% of people with FSS had a history of an anxiety or depressive disorder, per standard diagnostic criteria,15 and people with a history of anxiety or depressive disorders were nearly 3 times more likely to have FSS.19 In another study,18 investigators examined a sample of patients in Health Maintenance Organization plans and found that half of the patients in the top 10% of ambulatory care users had anxiety, depression, or somatization.

Functional somatic syndrome has also been associated with a history of childhood abuse or neglect.20 Bonvanie et al21 discovered that stressful life events in adolescence were associated with FSS, even when adjusting for levels of functional somatic symptoms, anxiety and depression symptoms, and socioeconomic status before the stressful life event. In an epidemiologic study of more than 1200 women, Walker et al22 concluded that the number of symptoms without clear medical explanation that a patient presented with directly correlated to the number of reported adverse childhood experiences. In addition, FSS can develop as a result of natural life stressors. For example, after the San Francisco Bay Area earthquake of 1989, a sample of residents reported significantly greater numbers and frequency of dissociative symptoms, including derealization and depersonalization; distortions of time; and alterations in cognition, memory, and somatic sensations up to 4 months after the earthquake compared with their baseline symptoms 1 week before the earthquake.23 These nonspecific cognitive and somatic symptoms represent a subjective index of affective distress with low correlations to objective testing.24,25

Although patients with FSS report more symptoms and higher degrees of disability than those with traditionally defined medical or psychological conditions, physicians may perceive symptom severity and disability as less severe when the symptoms are not medically supported.7 Apex clinical care is always a goal, but many physicians are not trained in how to assess or manage symptoms of FSS. A survey of medical students in the United Kingdom showed that no specific course covered the topic of FSS, and, if the topic was covered, it was inconsistent and disparate across medical schools.26 In my experience, this lack of training regarding FSS and discrete medical profiles can lead to physicians feeling mild discomfort or anxiety and resentment when patients present with FSS. These feelings can also stem from limited exposure and training in enhanced care, which includes a treatment model that draws on explanations for symptoms in broad biopsychosocial terms, in general practice settings.27 Osteopathic physicians, with their holistic approach to patient care, are in a unique and advantageous position to offer enhanced care to patients with FSS.

Unreported stressors may be the most damaging to physical and mental health, whereas disclosure of stressors can result in improved measures of cellular immune system function and fewer health care visits.28 Stressors may go unreported because it may be more comfortable for patients with FSS to focus on physical symptoms rather than exploring mental stressors.29 It is critical to investigate FSS symptoms in the context of ongoing stress, but patients may experience this assessment as hostile and adversarial. If an adversarial mindset dominates the encounter, then exploring psychosocial factors becomes difficult. Page and Wessely7 proposed that such encounters can be viewed by patients as rejecting, colluding, or empowering. Patients who feel rejected will continue to seek other opinions and resources (eg, outpatient visits, emergency department visits, medical tests and procedures, medication).7 Physicians who collude with patients can encourage iatrogenic illness and overuse of medical tests, often with adverse effects.7 Collaborating with patients and empowering them to be a part of controlling their symptoms is the most beneficial approach for the patient, the physician, the patient's family, and the health care system because these patients are less likely to feel rejected, can work with the physician on proposed treatments, and are less likely to seek unnecessary resources.7

Patients with FSS must be approached differently than other patients. The physician must keep in mind that, despite research28,29 showing a strong association with psychological factors, patients with FSS often present with only physical symptoms.30 Well-documented stressors, medical history, and behavioral health conditions are imperfectly recalled and make the prospect of illusory mental health likely to be unintentional.31 For example, as many as 40% of people who had documented abuse in childhood fail to report it, even if they are directly questioned about it.32 Patients with FSS also tend be biased in their recall of symptoms before an onset marker (the start of the first symptoms identified by the patient to cause a change in their health) and may minimize past symptoms.33 Furthermore, they are more likely to incorrectly report previous medical diagnoses or test findings and overpathologize their medical history than patients with a confirmed disease.34 On the one hand, directly confronting the lack of evidence for a confirmed medical cause of a patient's symptoms is likely to put them on the defensive and leave them feeling rejected. On the other hand, accepting subjective reports without skepticism or objective evidence can lead to collusion. Contrary to many patients, those with FSS become more anxious when more tests are run, even if the results are negative.17 These patients tend to catastrophize their illness as being rare and serious if it cannot be detected by standard tests and even minor or irrelevant abnormalities in the results become hypothesis-generating, which then increases their anxiety.7 The Figure illustrates this cycle.

Figure.

The presentation and assessment cycle of a patient with functional somatic syndrome.

Physicians can take certain actions to aid in a positive patient-physician relationship, including listening openly, documenting a detailed medical history, and documenting the exhaustive list of symptoms.35 This approach includes asking about the onset and course of the symptoms and, specifically, how patients are functionally limited by the symptoms. Part of this initial encounter includes gently probing for life stressors, particularly in a manner that allows the patient to begin to externalize the source of stress.35 It is also helpful to ask similar questions in multiple different ways to ensure consistency and limit corroboration. Often, the particular end-state behavioral manifestation of FSS relates to modeling, which highlights the importance of asking whether the patient knows anyone with a similar condition.35 If patients have been evaluated or treated for FSS before, it is important to ask about their previous experiences to ensure that negative experiences are not repeated and expectations can be accurately managed. Then, a routine physical examination and basic tests (eg, complete blood cell count, comprehensive metabolic panel, thyroid-stimulating hormone test) can be ordered, per the physician's judgment. Once an organic cause has been excluded, further examination and investigation should only be initiated if new symptoms develop.7 Given the complex nature of the symptoms and history presented by patients with FSS, it can be beneficial to both the patient and the physician to develop visual aids, as suggested by Stone et al,35 that document patients’ symptoms, stress level, and duration of symptoms.

Stone et al36 reported that more than 90% of patients with FSS found it offensive to be told that their symptoms were all in the mind, and as many as 50% of patients with FSS considered it offensive to be told their condition was psychosomatic or medically unexplained.36 Fewer patients with FSS (<15%) took offense to a term like functional somatic to describe their symptoms. Patients with FSS respond in a more positive way when they are offered reassurance (eg, “I have looked carefully, and there seems to be nothing of serious or life-threatening concern”) and a functional approach to management (eg, “Your body is not working as well as it should,” “Perhaps your body is trying to tell you something,” “Everyone copes with stress in different ways”) than being told overtly there is no medical explanation for their symptoms or trying to convince them of an isolated psychological cause.37

Because psychological symptoms frequently remain unrecognized or untreated in patients with FSS, these patients will often express dismay, trepidation, or even rejection of suggestions to see a behavioral health professional.38 They may feel as though the physician is rejecting their claim to legitimate medical symptoms and abandoning them. Physicians can have more success with patients by standing with them and helping them to understand the results of medical tests completed in terms of a broad umbrella of factors influencing their condition.

Management

There are 3 common ways that patients with FSS react to their symptoms.39 Patients who sought to understand the psychological and physical interplays of their symptoms had better success in life; patients who sought symptom relief and legitimization from physicians were less able to carry out independent activities of daily living and felt entitled to be excused from normal social obligations; and patients who expressed worry about missed diagnoses sought excessive medical help, protested when their demands for investigations or treatments were resisted, and were not reassured by negative test results or their physician's benign assessment.39

Although patients with FSS can have positive medical test results that indicate an underlying physiological issue, the resulting symptoms and disabilities are not entirely explained by or are more severe than expected by the organic syndrome alone.40 An FSS can have physiologic examination findings associated with it, because it is causing real symptoms, but one must be cognizant that it is also significantly overrepresented in terms of comorbid psychological conditions.27 Functional somatic syndrome with physiologic examination findings associated with them share more similarities than differences with other symptoms of FSS in terms of management; thus, behavioral health treatment remains an integral part of optimal management.41,42

Positive functional restoration outcomes (the ability to engage in independent activities of daily living) are more likely when physicians take a collaborative approach with patients.43 Collaborating with patients includes changing their attitudes about their symptoms, helping them to understand that their symptoms are not life-threatening or disabling, and alleviating dysfunctional thoughts that create anxiety regarding their health.37 A qualitative review of different ways to manage symptoms of FSS suggests that a combination of the following 3 factors is most effective: (1) create a nonthreatening, therapeutic environment; (2) provide interventions that do not require specialized training in behavioral health (eg, motivational interviewing, tangible explanations, reassurance, regularly scheduled appointments); and (3) recommend specific interventions with behavioral health specialists and psychotropic medication.44 Researchers have suggested different approaches to the treatment of patients with FSS: an organ-oriented approach (ie, symptomatic treatment), a cognitive interpersonal approach (ie, cognitive processing of health-related anxiety), or a contextual approach (cultural beliefs, workplace characteristics, incentives).11 Regarding the latter approach, the family system should be kept in mind as well. An association has been found between FSS behaviors and attention-seeking or withdrawal behaviors of significant others.45 It has also been found that dependency on a significant other predicted greater long-term health care use (>90 days), and yet, a literature search revealed no studies of families of patients with FSS.45 Patient-physician visits that include a brief physical examination instead of ordering tests based on subjective reports of symptoms translates to decreased health care use and better physical functioning in patients with FSS, even though this approach may run counter to most medical training.46

The most consistent finding in randomized controlled trials (RCTs) has been the benefit of cognitive behavioral therapy in patients with FSS. A study44 concluded that cognitive behavioral therapy is an evidence-based treatment for FSS. Several reviews also found evidence supporting the use of cognitive behavioral therapy in the management of FSS.41,42 In a review of RCTs, 85% of the included studies showed that the use of cognitive behavioral therapy significantly benefited patients with FSS.47 In a meta-analysis of 27 studies, cognitive behavioral therapy had a small to moderate positive effect in patients with FSS.48 A study that examined patients in secondary care clinics with chronic fatigue syndrome showed that 3 to 14 sessions of cognitive behavioral therapy resulted in reduced fatigue and increased physical function.49 In another study, patients with FSS who completed an average of 7 cognitive behavioral therapy sessions reported fewer days spent in the hospital and fewer visits to the emergency department, suggesting that the sessions helped patients avoid catastrophizing physiologic experiences that can lead to emergent, costly care.50 In a small pilot study examining the use of cognitive behavioral therapy in a primary care setting, a 1-hour initial session and three 20-minute sessions had an effect size of 0.5 for physical symptom reduction, and 72% of patients with FSS reported that the intervention helped them to effectively cope with their symptoms.51 In a meta-analysis of 13 RCTs examining mindfulness-based stress reduction and cognitive therapies, a small to moderate positive effect was found on pain, symptom severity, depression, anxiety, and quality of life in patients with FSS that underwent these therapy sessions.

In addition to positive patient outcomes, cognitive behavioral therapy is also a cost-effective way to manage FSS.52 When comparing the effect of mindfulness therapy with medical care from a specialist, Fjorback et al53 showed that after 15 months of treatment, about half as many patients in the mindfulness therapy group were receiving disability, and their total direct health care costs were an average of $1754 less, including the cost of therapy, than those in the specialist care group.

A Cochrane review that analyzed the use of medication to manage symptoms in patients with FSS found that there was no evidence supporting the efficacy of tricyclic antidepressants over a placebo, and there was low-quality evidence of benefit from new-generation antidepressants and natural products, such as St. John's wort.54 Data have shown that escitalopram is more effective than placebo in managing FSS at 6 and 12 weeks, but long-term term follow-up information is not available.55 The benefit of antidepressants is conflicting, though, as a study found that symptoms in patients with FSS in the otolaryngologic region could be successfully managed with selective serotonin reuptake inhibitors.56 Systematic reviews examining FSS have indicated that antidepressants can be beneficial even if overt evidence of depression is not present,57 but Stone et al37 suggested that patients should be informed that their symptoms can improve without medication, and this option is merely to explore all avenues of treatment.

Physical treatments (ie, exercise, autogenic training, progressive muscle relaxation) for patients with FSS have shown promise in a number of studies. A Cochrane review showed that exercise has positive effects on sleep habits, fatigue, physical functioning, and self-perceived health in patients with FSS, similar to the effects of cognitive behavioral therapy, with no documented adverse effects.58 Graded exercise therapy is the most frequent physical treatment recommended, with programs emphasizing the role of physiologic dysregulation to manage fatigue. An RCT that compared the effects of graded exercise therapy with that of conventional medical care in patients with chronic fatigue syndrome showed that the exercise group had greater improvement in symptoms and less fatigue than the standard medical care group.59 In another study examining patients with chronic fatigue syndrome, 69% attained adequate physical functioning on the SF-36 physical functioning subscale60 after participating in a graded exercise therapy program vs 6% of control patients.61 In addition, cognitive behavioral therapy combined with graded exercise therapy has led to clinically significant benefit for multiple conditions, including chronic fatigue syndrome and fibromyalgia.62,63 Additionally, a 10-week RCT64 was conducted to compare psychophysiologic management strategies (eg, stress education, heart rate variability training, progressive muscle relaxation with electromyography feedback, autogenic training) with visits with a psychiatric physician for care while waiting for psychophysiologic treatment. The psychophysiologic treatment–only group showed a decrease in depressive and physical symptoms and an increase in functional abilities by the end of the treatment.

Many other options have been suggested for the management of symptoms of FSS, including standard medical treatments (eg, medication, surgical procedures), reattribution therapy, psychodynamic therapy, hypnosis, and herbal remedies, but these either do not have support in the empirical literature or the support they have is based on anecdotal evidence, case studies, or small case series without appropriate comparison groups, including sham or placebo procedures, and without appropriate blinding to the treatment groups, raising their risk of bias.

Conclusion

Patients with FSS present a unique challenge to physicians, as these patients do not have confirmatory medical findings to explain their symptoms, and traditional approaches to management of symptoms, such as medication, are unlikely to be beneficial in isolation. Although they can be complex, perplexing, and enigmatic, the symptoms of FSS are no less real or debilitating than those caused by medically explained illnesses, and these patients are no less deserving of medical attention. Symptoms of FSS can be successfully managed if physicians take a collaborative and inclusive approach to care. Positive outcomes do not depend on convincing patients of the psychological nature of their symptoms. Instead, physicians can best care for these patients by helping them recognize the multitude of factors that may be affecting their lives and working to restore them to healthy functioning. Osteopathic physicians are in a prime position to provide this comprehensive biopsychosocial approach to care that can lead to optimal outcomes in patients with FSS.